MinisterofDOOM wrote:2.5" should be fine. Not real need to go bigger than 3.0" even with boost. More important than diameter is cleaning up the path. As noted above, Y-pipe is definitely a must if you want to get the most out of the S/C.
I ran a Magnaflow muffler on my VG max (different than the VQ Max but still subject to the Japanese farts with the wrong muffler like the VQ). It kept the tone deep and smooth, without any popping or flatulence. A resonator will also help clean up the sound.There's a thread floating around called "what exhaust are you running" or something like that. Do a search for threads with "exhaust" in the title in the Maxima forum and you should find it.
Yea for a s/c you really dont need anything larger than 2.5 but as in my turbo car i am running 3 inch but thats a whole diff ball game. I think y pipe, 2.5 catback and a high flow cat you should be fine.